65RFE Issue!! Lugging engine between 50-90kmh low rpm, struggles to downshift on light acceleration.

[Colin7761]

65RFE 5.7 HEMI. No DTCs at all.
rpms will drop to around 1000 and when lightly putting the pedal down the engine feels like it’s lugging and struggling to downshift. The TCC lockup is off during the problem. Line pressure is good. Anyone know what is actually happening?

 

[Burla]

Does it act the same in tow haul mode? Check fluid level warm in neutral?